It's time for engine out and rebuild it.

I made a decision to by my car, a 2003 Carrera 4s. It was cold as instructed previous to it being started, and yes out of the left hand side came a little smoke. Now, that would have put many off, but to me it was a clear sign that things were not right. So i bought it at a good price that i was happy to pay. 5000 miles later, it was running on 5 cylinders, one coil pack decided to give up on me, so I made the decision to remove the engine and rebuild it ,whilst the onset of winter is imminent. I called on the services of Pie performance to over see the engine rebuild, and Hartech to do the machining and supply of piston's. Pie have looked after my previous Porsche, and gave me the confidence to farm out any work to them. I got a call from Chris at Pie saying the engine was out of the tv car, and stripped down, both cylinders were on a pallet ready to go to Hartech's, would I like to pop in and see them, oh and by the way, someone has had the engine in bits, and things are not as they should be, but dont worry, it can be put right. Here is some of the progress.

excellent, just a like for like engine rebuild ? out of interest how many miles did the car have before it started to have engine issues ?

Not like for like, but an improvement in all area 's and another 300cc's. The mileage is 87000 approx, however, the head on one side has been off, but why is not apparent......Yet !

3.9

Fantastic progress already! This is going to be a very interesting build thread. Before Hartech machine away the old cylinders it would be great to get some pics showing the extent of any scoring in each of the numbered bores, and their respective piston skirts.

Okay Bananaz, here is the left hand bank, numbers 4 to 6. As you can see, some serious scoring in both photo's. It is usual I am led to believe that number 5 is normally the culprit, but very little was apparent.

Very interesting photos. What were the symptoms experienced prior to deciding to push the rebuild button? Was it idling noise, oil consumption, smoky running etc.? Was oil fouling in one of the scored cylinders the reason that the car was running on 5 only, or was this due to a dead coil pack? Sorry for the barrage of questions, but I have the same car almost exactly so am v. Interested!

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Bananaz, your "barrage of questions, is not seen as a negative but interesting for those on here who are following this thread. That first smokey start up when I first looked at the car with a view to purchasing it was followed through out every cold start up. When it was warm it would be reduced, but still there would be a little smoke. When hot the "dreaded" idling noise was always there, sometimes quieter, but there. Now oil consumption, this was a little harder to use as a reason for a rebuild. I had oil leaking from the RMS. area, and all the other " normal" area's that a porsche engine has wet patches. It therefore did use oil, 750ml per 1000 miles. I would rule out fouled plugs as the reason for running on 5 cylinders, there were two very poor cylinders that burnt oil, and both on the same bank. Further more, the coil pack shields were missing on the same side, and the coil packs were cracked and starting to "delaminate" this was their down fall, and therefore missing on one cylinder. I am guessing that your questions are specific to your findings of your own car, and my answers will only go to prove what you may already have thought.

agree Mark, following this this thread with interest

My engine has done approximately 87000 miles, and as can be seen from the two photo,s the bearings are showing signs of wear. They are very polished on the thrust faces. Now I dont have any other engines to compare the bearing shells too, however, when I broached this subject with the tech who took my engine apart, and who will be rebuilding it, he remarked that the wear was that of an engine that had covered that sort of mileage, I guess that could be improved by regular oil changes, and good quality oil.

Nothing wrong with those bearings, just look like they've covered that mileage. There is chance they're newer as the engine has been stripped before. It's when they're through to the copper and beyond you may worry. If they all look the same it's fine. You usually see the extent of wear with the flywheel side the worse, up to the oil pump side the best.

I dread to think what mine look like at 169k!

Alex, thank you for your input. Funny enough, the thrust washers on the crankshaft main bearings had both worn, but one more than the other, I can't remember, but I have a feeling the one furthest from the flywheel. Any reason why ?

Whilst at my indy last week, I bought some items of my Porsche home to work on. Todays item was the air box. After a lot of time cleaning the oily residue off, it started to look reasonable. A new filter and the oil collector which was only just holding together will be ordered. Oh, and the last photo. ............Had to be done.

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Interesting findings on the bearings! My car is new to me, and I specifically looked for a car without any obvious bore-scoring symptoms. One car that I looked at with 115k miles was very noisy at hot idle. It sounded a bit like an exhaust manifold leak but was piston slap. I paid to have it borescoped and it confirmed my suspicions. The service manager of the specialist that scoped the car assessed it at 7/10 progression. At that point, more than one piston would have completely shed the ferrite skirt coating and be galling against the bore itself. The car I ended up buying has 143k miles. What could go wrong lol? There is fairly recent IMS/RMS Clutch/Flywheel work, but other than that, the engine appears original. The usual signs of scored cylinders (blackened left tailpipe, puffs of smoke from cold, noisy hot idle, high oil consumption, plug fouling) are absent. It's too early to comment on oil consumption per 1k miles, but so far it has run nicely for the first 400 miles or so and the oil pressure is perfect. The funny thing about bore scoring is that it it occurs at any mileage. It's not the case that if you get past a certain mileage that you therefore have a good'un and that you are safe. It's also not the case that if you buy a genuine low-mileage example that you're safe either. Either of these two sorts of cars can have scoring issues without fear or favour. The crazy thing about the UK market for the 996 C4S is that it values cars based mainly on mileage. Other factors such as transmission, colour, owners, and detailed history are also important - but mileage is the key factor influencing price. A car with 150k can be had for 17+ grand whereas a car with under 50k can fetch 32+ grand at a dealer. At both ends of this spectrum you can find well maintained, ready to go examples. The killer question: Which one is least likely to have bore-scoring? The killer answer: Nobody can tell you, it's fairly random! All you can do is get a borescope on any car you are serious about or buy from an indie that does this for you. With that in mind I went in privately at the lower price point, figuring the same as the OP - that if I ever have to rebuild the engine - at least I've left the most financial headroom possible. All engines will need rebuilding at some point. To get there, you only need to keep driving them!! There are a lot of scored cars out there, and many come up for sale. The rebuild cost is such that many owners elect to cut their losses and trade out of the car. These cars then pop up in the non-specialist dealer network all the time, many of whom don't even know there is an issue with them. Caveat emptor and buy them at the right price like the OP.